I create multiple Google Alert based on multiple keyword (my niche) , so when a content containing my keyword is published on the web, i am immediately alerted by Google (email or rss), so i am the first to comment & participate on blogs,forums,... and put my backlink.
It's natural and spontaneous backlink strategy.
How to :
1 - Access to Google Alerts - Monitor the Web for interesting new content
2 - Enter you keyword & set params